Should a Refluxing Internal Diversion Be Considered a Temporizing Procedure? Extended Follow-up and Outcomes After Side-to-Side Ureterovesicostomy for Primary Obstructive Megaureter in Young Children.

PURPOSE: We describe long-term outcomes, including UTIs and need for reimplantation, after ureterovesicostomy (UV) as a lasting surgical procedure for children with primary obstructive megaureter (POM). MATERIALS AND METHODS: Children referred to our institution between 2016 and 2023 who underwent refluxing UV were analyzed. POM was defined as hydroureteronephrosis with distal ureteral dilatation > 7 mm and a negative workup for other etiologies of hydronephrosis. We assessed for surgical outcomes, complications, rate of UTI, and improvement in upper tract dilatation. Statistical analyses assessed for change in hydronephrosis metrics over follow-up. RESULTS: Among 183 patients diagnosed with POM, 47 (24%) underwent UV. Median age of presentation, surgery, and follow-up was 2, 9, and 43 months, respectively. A total of 7 patients developed 30-day complications: Clavien-Dindo grade 1 in 2 (transient urinary retention) and grade 2 in 5 (UTIs). During monitoring 14 (30%) developed UTIs and 7 (15%) required ureteral reimplant or UV takedown. After surgery there was a significant decrease in the proportion of patients with high-grade hydronephrosis, anteroposterior renal pelvis diameter, and maximum ureteral dilatation. CONCLUSIONS: Refluxing UV is a safe alternative to cutaneous diversion in POM. Most patients had improvement in upper tract dilatation with an acceptable short-term complication rate and need for reoperation (in comparison to routine later reimplantation). Our experience suggests that monitoring alone after UV is feasible, and that selective subsequent reconstruction is a reasonable strategy.

A new technique for the treatment of ureteric stricture after kidney transplantation.

OBJECTIVE: To evaluate the safety and effectiveness of endoscopic treatments with Allium® metal ureteric stent (AMUS) for ureteric strictures after kidney transplantation (KT). PATIENTS AND METHODS: In a prospective manner, we gathered clinical data from 68 patients who underwent endoscopic treatments with AMUS for ureteric strictures after KT between January 2019 and March 2022. The definition of surgical success was the unobstructed drainage of the AMUS, or in cases where there was AMUS migration, occlusion or encrustation and subsequently removed, there is no worsening of renal hydronephrosis in the patient during the follow-up period. RESULTS: Based on the specific circumstances of the ureteric strictures, three distinct types of surgery were selected for treatment. The overall success rate of endoscopic treatments for ureteric strictures following KT was 90% (61/68) during a follow-up period of 1 year. Surgical complications included haematuria (18%), pain (10%), urinary tract infections (7.4%), and lower urinary tract symptoms (7.4%). The incidences of stent migration, occlusion, and encrustation were 10%, 2.9%, and 1.5%, respectively. Postoperatively, significant improvements were observed in various parameters. At 1 month after surgery, there was a notable decrease in blood creatinine levels (105.5 vs 90.4 mol/L), urea nitrogen levels (6.6 vs 5.4 mmol/L), and hydronephrosis volume (64.4 vs 43.9 mL). Additionally, the serum estimated glomerular filtration rate increased from 49.5 to 64.4 mL/min/1.73 m2. The follow-up results of patients at 1 year after surgery were similar to those observed at 1 month after surgery. CONCLUSIONS: Systemic endoscopic treatments with AMUS were found to be safe and effective for ureteric strictures after KT with short-term follow-ups. This technique offers a novel option for the treatment of post-KT strictures.

Malignant ureteral obstruction: comparison of metallic, 8 French and 6 French ureteric stents after failure of initial ureteric stent.

PURPOSE: Malignant ureteric obstruction is a significant management challenge. The failure of ureteric stents often leads to long-term nephrostomy tubes. This is delayed for as long as possible due to its' associated morbidity. Several types of ureteric stents are available, however there is little evidence demonstrating which stents are better for preventing progression to nephrostomy tubes. This study looked to determine whether a new 6 French (Fr) polymer stent, 8Fr polymer stent or metallic stent achieved a longer functional duration once the initial polymer ureteric stent failed. METHODS: A retrospective, longitudinal study was performed at a single tertiary institution. All patients who underwent ureteric stenting with a 6Fr polymer stent for malignancy between 2010 and 2020 were included. Patients were followed up until death with ureteric stent in situ or permanent nephrostomy tube insertion. RESULTS: A total of 46 patients (66 ureters) had ureteric stents inserted for malignancy. From initial ureteric stent failure, 10 stents were changed to a new 6Fr polymer stent, 42 were changed to an 8Fr polymer stent and 14 were changed to a Resonance® 6Fr metallic stent. The Resonance 6Fr metallic stent had the longest median functional duration of 14 months (p = 0.012). CONCLUSION: Resonance® 6Fr metallic stents appear to have a significantly longer functional duration than a new 6Fr polymer stent or 8Fr polymer stent, which may allow patients to enjoy a better quality of life and delay permanent nephrostomy tube insertion.

Transient ureteral obstruction after mini-percutaneous nephrolithotomy is associated with stone volume and location: results from a single-center, real-life study.

PURPOSE: To evaluate the rate of and predictors of ureteral obstruction after mini-percutaneous nephrolithotomy (mPCNL) for kidney stones. METHODS: We analyzed data from 263 consecutive patients who underwent mPCNL at a single tertiary referral academic between 01/2016 and 11/2022. Patient's demographics, stone characteristics, and operative data were collected. A nephrostomy tube was placed as the only exit strategy in each procedure. On postoperative day 2, an antegrade pyelography was performed to assess ureteral canalization. The nephrostomy tube was removed if ureteral canalization was successful. Descriptive statistics and logistic regression models were used to identify factors associated with a lack of ureteral canalization. RESULTS: Overall, median (IQR) age and stone volume were 56 (47-65) years and 1.7 (0.8-4.2) cm3, respectively. Of 263, 55 (20.9%) patients showed ureteral obstruction during pyelography. Patients without ureteral canalization had larger stone volume (p < 0.001), longer operative time (p < 0.01), and higher rate of stones in the renal pelvis (p < 0.01) than those with normal pyelography. Length of stay was longer (p < 0.01), and postoperative complications (p = 0.03) were more frequent in patients without ureteral canalization. Multivariable logistic regression analysis revealed that stone volume (OR 1.1, p = 0.02) and stone located in the renal pelvis (OR 2.2, p = 0.04) were independent predictors of transient ureteral obstruction, after accounting for operative time. CONCLUSION: One out of five patients showed transient ureteral obstruction after mPCNL. Patients with a higher stone burden and with stones in the renal pelvis are at higher risk of inadequate ureteral canalization. Internal drainage might be considered in these cases to avoid potential complications.

Risk factors for migration of retrievable covered expandable metallic stent in patients with persistent benign ureter strictures.

PURPOSE: The purpose of this study is to evaluate the incidence, risk factors, and salvage management of retrievable covered expandable metallic stent (RCEMS) migration in patients with persistent benign ureter strictures. MATERIALS AND METHODS: A retrospective study was performed on 117 consecutive patients who underwent implantation of RCEMS. Univariate and multivariate analyses were used to identify prognostic factors for stent migration, including stricture location and length, hydronephrosis-cortex ratio, ureteral dilation, and the diameter of the narrowest portion of the stricture. RESULTS: Stent migration occurred in 22 (19.5%) of 113 patients who met inclusion criteria. Of the 22 patients, 16 (72.7%) had ordinary ureteral stricture, 3 (13.6%) had stricture in transplanted kidneys, and 3 patients (13.6%) had ureter stricture in orthotopic neobladders. The mean creatinine for the entire cohorts showed significant improvement (p = 0.038). Multivariate analysis identified the following prognostic factors for migration: distal ureteral stricture (p = 0.006), patients who underwent balloon dilation (p = 0.003), hydronephrosis-cortex ratio ≧10 (p = 0.017), larger diameter of wasting of RCEMS (p < 0.001), and patients with a shorter stricture length (p = 0.006). Salvage management was required in 4 of the 22 patients. The strictures in the remaining 18 patients improved with observation. CONCLUSIONS: Stent migration is more likely to occur in patients with the five prognostic factors mentioned above. Our study developed a nomogram to predict stent migration in patients with ureteral strictures treated using RCEMS.

An international delphi survey and consensus meeting to define the risk factors for ureteral stricture after endoscopic treatment for urolithiasis.

PURPOSE: Iatrogenic ureteral strictures (US) after endoscopic treatment for urolithiasis represent a significant healthcare concern. However, high-quality evidence on the risk factors associated with US is currently lacking. We aimed to develop a consensus statement addressing the definition, risk factors, and follow-up management of iatrogenic US after endoscopic treatment for urolithiasis. METHODS: Utilizing a modified Delphi method, a steering committee developed survey statements based on a systematic literature review. Then, a two-round online survey was submitted to 25 experts, offering voting options to assess agreement levels. A consensus panel meeting was held for unresolved statements. The predetermined consensus threshold was set at 70%. RESULTS: The steering committee formulated 73 statements. In the initial survey, consensus was reached on 56 (77%) statements. Following in-depth discussions and refinement of 17 (23%) statements in a consensus meeting, the second survey achieved consensus on 63 (86%) statements. This process underscored agreement on pivotal factors influencing US in endoscopic urolithiasis treatments. CONCLUSIONS: This study provides a comprehensive list of categorized risk factors for US following endoscopic urolithiasis treatments. The objectives include enhancing uniformity in research, minimizing redundancy in outcome assessments, and effectively addressing risk factors associated with US. These findings are crucial for designing future clinical trials and guiding endoscopic surgeons in mitigating the risk of US.

Risk and protective factors for secondary procedures after endoscopic dilatation of primary obstructive megaureters.

PURPOSE: High-pressure balloon dilatation (HPBD) of the ureterovesical junction with double-J stenting is a minimally invasive alternative to ureteral reimplantation or cutaneous ureterostomy for first-line surgical treatment of primary obstructive megaureter (POM). The aim of our study was to identify the risk factors associated with the need for secondary procedures due to HPBD failure. METHODS: Prospective data were collected from patients who underwent HPBD for POM between 2007 and 2021 at a single institution. The collected data included patient demographics, diagnostic modalities, surgical details, results, and follow-up. Multivariate logistic regression analysis was performed. RESULTS: Fifty-five ureters underwent HPBD for POM in 50 children, with a median age of 6.4 months (IQR: 4.5-13.8). Nineteen patients (37.25%) underwent secondary ureteric reimplantation, with a median of 9.8 months after primary HBPD (95% CI 6.2-9.9). The median follow-up was 29.4 months (IQR: 17.4-71). Independent risk factors for redo-surgery in a multivariate logistic regression model were: progressive ureterohydronephrosis (OR = 7.8; 95% CI 0.77-78.6) and early removal of the double-J stent. A risk reduction of 7% (95% CI 2.2%-11.4%) was observed per extra-day of catheter maintenance. The optimal cut-off point is 55 days, ROC curve area: 0.77 (95% CI 0.62-0.92). Gender, distal ureteral diameter, pelvis diameter, dilatation balloon diameter and preoperative differential renal function did not affect the need for reimplantation. CONCLUSIONS: The use of a double-J stent for at least 55 days seems to avoid the need for a secondary procedure. Therefore, we recommend removing the double-J catheter at least 2 months after the HBPD.

Ureteral stricture rate after endoscopic treatments for urolithiasis and related risk factors: systematic review and meta-analysis.

PURPOSE: We aimed to accurately determine ureteral stricture (US) rates following urolithiasis treatments and their related risk factors. METHODS: We conducted a systematic review and meta-analysis following the PRISMA guidelines using databases from inception to November 2023. Studies were deemed eligible for analysis if they included ≥ 18 years old patients with urinary lithiasis (Patients) who were subjected to endoscopic treatment (Intervention) with ureteroscopy (URS), percutaneous nephrolithotomy (PCNL), or shock wave lithotripsy (SWL) (Comparator) to assess the incidence of US (Outcome) in prospective and retrospective studies (Study design). RESULTS: A total of 43 studies were included. The pooled US rate was 1.3% post-SWL and 2.1% post-PCNL. The pooled rate of US post-URS was 1.9% but raised to 2.7% considering the last five years' studies and 4.9% if the stone was impacted. Moreover, the pooled US rate differed if follow-ups were under or over six months. Patients with proximal ureteral stone, preoperative hydronephrosis, intraoperative ureteral perforation, and impacted stones showed higher US risk post-endoscopic intervention with odds ratio of 1.6 (P = 0.05), 2.6 (P = 0.009), 7.1 (P < 0.001), and 7.47 (P = 0.003), respectively. CONCLUSIONS: The overall US rate ranges from 0.3 to 4.9%, with an increasing trend in the last few years. It is influenced by type of treatment, stone location and impaction, preoperative hydronephrosis and intraoperative perforation. Future standardized reporting and prospective and more extended follow-up studies might contribute to a better understanding of US risks related to calculi treatment.

Magnetic Compression Anastomosis of Benign Short-Segment Ureteral Obstruction.

PURPOSE: To investigate the feasibility, safety, and effectiveness of magnetic compression anastomosis of benign short-segment ureteral obstruction. MATERIALS AND METHODS: Patients referred for failure of ureteral double-J stent placement because of impassable benign ureteral obstruction were included. Eleven patients (11 ureters) with a mean age of 57.5 years (range, 19-85 years; 8 women) underwent ureteral magnetic compression anastomosis. All patients had indwelling nephrostomy catheters. In all patients, anterograde and retrograde ureteral stent placements were unsuccessful using either interventional or cystoscopic access. Ureteral magnetic compression anastomosis was performed as a 2-step procedure. In the first step, magnets were placed. In the second step, the stricture was traversed via magnetic compression anastomosis. Successful establishment of anastomosis and ureteral double-J stent placement were considered technical success. The mean time for complete magnetic adherence and fluoroscopy time for each procedure were recorded. RESULTS: Five patients (45%) had an ileal conduit. The technical success rate was 91% (n = 10/11). The mean time for magnetic adherence was 5.7 days (SD ± 1.3). The mean single-rotation fluoroscopy times during the first and second steps of the procedure were 9.45 minutes (SD ± 2.09) and 15.70 minutes (SD ± 2.62), respectively. Magnets were removed with the support of either balloon catheters (n = 9) or biopsy forceps (n = 2). No procedure-related adverse events occurred. CONCLUSIONS: Magnetic compression anastomosis of benign ureteral obstruction is feasible and safe and can be performed in an interventional radiology (IR) suite without the need for endoscopy.

Percutaneous Nephroureteral Stent Placement and Antegrade Forceps Biopsy of Ureteral Obstruction.

PURPOSE: To evaluate the feasibility of percutaneous transluminal ureteral biopsy (PTUB) combined with percutaneous nephroureteral stent placement for ureteral obstruction under fluoroscopy. MATERIALS AND METHODS: From September 2011 to July 2021, 37 patients (27 men and 10 women; median age, 65.0 years) who experienced ureteroscopic biopsy failure or refused or were unable to undergo ureteroscopic biopsy underwent PTUB for ureteral obstruction during nephroureteral stent placement under fluoroscopic guidance. Data on technical success, early adverse events, and radiation dose were collected. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy (OA) of PTUB were analyzed. RESULTS: The technical success of PTUB was 89.2%, with a mean irradiation dose of 76.9 mGy·cm2 ± 12.2. A total of 67.6% (25/37) of the cases were correctly diagnosed with malignancy, whereas 8 cases were confirmed to be true negatives. There were 4 false negatives and no false positives. PTUB had a sensitivity, specificity, PPV, NPV, and OA of 86.2% (25/29), 100% (8/8), 100% (25/25), 66.7% (8/12), and 89.2% (33/37), respectively. Eleven patients (29.7%) experienced Grade 1 adverse events (transient aggravated hematuria). CONCLUSIONS: PTUB appears to be a safe and effective alternative to ureteroscopic biopsy for ureteral obstruction.

Safety and efficacy of thermo-expandable metallic stent in ureteral stricture following gynecological malignancy surgery and radiotherapy: a single center experience with 33 cases.

BACKGROUND: The effectiveness of metallic stents in treating ureteral strictures following surgery and radiotherapy for gynecological tumors is currently uncertain. We aimed to investigate the efficacy and safety of thermo-expandable metallic stent (Memokath) in the treatment of ureteral stricture after radiotherapy for gynecological tumors. METHODS: In this descriptive cross-sectional study, 27 patients with ureteral stricture were treated with Memokath stent after gynecological tumor radiotherapy with or without chemotherapy that was admitted to our hospital from August 2021 to August 2023. Clinical data on efficacy, safety, and complications during stent insertion and indwelling were analyzed. RESULTS: The successful insertion of thirty-three stents in twenty-seven patients studied. The stenosis length was 10.14 ± 6.76 cm, and the hospitalization was 4.43 ± 1.83 days. One patient has died from the primary disease carrying a patency stent. The Kaplan-Meier graph showed that the cumilative patency rate of patients with thermo-expandable metallic stent were 92.4% (SD = 5.2%) in eight months, 77.4% (9.1%) in 12 months and 67.7% (SD = 12%) in 29 months, while the cumilative survival rate was 87.5% (SD = 11.5%) in 29 months. The stent patency was 81.48% and later complications of stent indwelling were 5/27, including refractory urinary tract infection (UTI) in three cases, stent migration, and stent intolerance respectively. The creatinine levels, hydronephrosis degree, and glomerular filtration rate improved after the operation, and the first two indicators were statistically significant. CONCLUSION: Memokath stent is a safe and effective treatment for ureteral stricture after surgery and radiotherapy with or without chemotherapy for gynecological tumors.

Unraveling the Complexities of Uretero-Enteric Strictures: A Modern Review.

PURPOSE OF REVIEW: The purpose of this review article is to provide a contemporary overview of benign uretero-enteric anastomotic stricture (UAS) management and outcomes. RECENT FINDINGS: In this article, we will review the most recent studies investigating UAS and evaluate etiology, potential risk factors, presentation, diagnosis, and management options, along with personal insight gained from our experience with managing this challenging reconstructive complication. Benign UAS is a relatively common long-term complication of intestinal urinary diversion, affecting approximately 1 in 10 patients. It is thought to be caused by ureteral tissue ischemia and fibrosis at the anastomotic site. Risk factors appear to include any that increase the likelihood of leak or ischemia; it is not clear if anastomotic approach impacts risk for stricture as well. Management options are varied and include endourologic, open, and robotic approaches. Endoscopic approaches may be less morbid but are considerably less effective than reconstruction performed after a period of ureteral rest.

Nephroptosis and ureteroinguinal incarcerated hernia mimicking acute appendicitis.

The involvement of kidney, perirenal fat, and ureter is a rare variant of inguinal hernia. We report a case of a 78-year-old man presenting with typical clinical signs of acute appendicitis. Ultrasonography and CT scan revealed ptosis of the right kidney with a major part of the perirenal capsule involved in a large right sided inguinal hernia with acute obstruction of the ureter and urostasis. Acute surgery was performed, involving resection of perirenal fat, liberation, resection, and neoimplantation of the ureter, and hernioplasty. The postoperative period was uneventful. This case illustrates diagnostic unpredictability of acute appendicitis as well as anatomic variety of inguinal hernias.

Complicated obstructive uropathy after kidney biopsy: A case report highlighting the risk of biopsy-related acute kidney injury in a patient with unilateral kidney hypoplasia.

Unilateral kidney hypoplasia is a congenital condition characterized by the underdevelopment of one kidney. Although often asymptomatic, it can cause severe renal complications in patients combined with contralateral renal injury, leading to acute renal failure. This case report describes a patient with unilateral kidney hypoplasia who underwent a kidney biopsy on the contralateral normal-sized kidney and subsequently developed oliguric acute kidney injury. This report discusses the challenges encountered while diagnosing and managing this rare case, highlighting the importance of awareness and recognition to perform timely intervention and optimize the patient's outcome.

Bricker versus Wallace ureteroileal anastomosis: A multi-institutional propensity score-matched analysis.

AIM OF THE STUDY: The aim of our study is to evaluate the difference in stricture rate between matched groups of Bricker and Wallace techniques for ureteroileal anastomosis. PATIENTS AND METHODS: A retrospective analysis of patients undergoing urinary diversion (UD) with Bricker and Wallace ureteroileal anastomosis at two university hospitals. Two groups of Bricker and Wallace patients were matched in a 1:1 ratio based on the age, sex, body mass index (BMI), Charlson comorbidity index (CCI), preoperative hydronephrosis, prior radiation therapy or abdominal surgery, pathologic T and N stages and 30-days-Clavien grade complications≥III. A multivariable Cox regression analysis was conducted to identify predictors of ureteroenteric stricture (UES) in all patients. RESULTS: Overall, 740 patients met the inclusion criteria and 209 patients in each group were propensity matched. At a similar median follow-up of 25 months, UES was detected in 25 (12%) and 30 (14.4%) patients in Bricker and Wallace groups, respectively (p = 0.56). However, only one patient in the Bricker group developed a bilateral stricture compared to 15 patients in the Wallace group, resulting in a significantly higher number of affected renal units in the Wallace group: 45 (10.7%) versus only 26 (6.2%) in the Bricker group (p = 0.00). On multivariable extended Cox analysis, prior radiotherapy, presence of T4 pelvic malignancy and nodal positive disease were independent predictor of UES formation. CONCLUSION: The technique of ureteroileal anastomosis itself does not increase the rate of stricture; however, conversion of two renal units into one is associated with a higher incidence of bilateral upper tract involvement.

Risk factors for adverse outcomes after pediatric pyeloplasty: A retrospective cohort study.

PURPOSE: To identify the risk factors for adverse outcomes after pediatric pyeloplasty. METHODS: We conducted a retrospective review of all children under the age of 14 years who underwent primary pyeloplasty for unilateral ureteropelvic junction (UPJ) obstruction at a single teaching hospital in Tunisia between January 1, 2013, and December 31, 2022. RESULTS: A total of 103 patients were included. Median age of patients at surgery was 27 months (interquartile range [IQR], 13-44). On ultrasound, median renal pelvic anteroposterior diameter was 3.2 cm (IQR, 2.3-4), and the median renal cortex thickness (RCT) was 2.5 mm (IQR, 2-3.5). Median differential renal function (DRF) on preoperative radionuclide renal scan was 40% (IQR, 30-46). Postoperative adverse outcomes occurred in 28 patients (27.2%). These included 19 cases of urinary tract infections (UTIs), 11 cases of UPJ restenosis, four cases of UPJ leakage, two cases of urinoma, and two cases of diversion-related complications. Multivariate logistic regression analysis revealed two factors significantly and independently related to postoperative negative outcomes: RCT <3 mm and DRF > 50%. CONCLUSION: Our study demonstrated that preoperative RCT on ultrasound of less than 3 mm and preoperative DRF on radionuclide renal scan of more than 50% were independent risk factors for adverse outcomes following pediatric pyeloplasty. These factors could be of interest in identifying, early on, patients who will develop postoperative negative outcomes, giving them more attention and support, and explaining the prognosis to the patient and family.

Japanese survey of perioperative complications and ureteral stricture after ureteroscopy with laser lithotripsy for upper urinary tract stones in multicenter collaborative study.

OBJECTIVES: This study aimed to investigate perioperative complications and the details of postoperative ureteral stricture after ureteroscopy with laser lithotripsy (URS-L) for upper urinary tract stones in Japan. METHODS: Patient data on intra- and postoperative complications after ureteroscopy using URS-L were retrospectively collected from multiple centers in Japan between April 2017 and March 2020 with the cooperation of the Japanese Society of Endourology and Robotics. Data included the number of patients undergoing URS-L, number and type of intra- and postoperative complications, and detailed characteristics of postoperative ureteral stricture. RESULTS: In total, 14 125 patients underwent URS-L over 3 years at 82 institutions. Annual URS-L numbers gradually increased from 4419 in 2017, to 4760 in 2018, and 4946 in 2019. The total complication rate was 10.5%, which was divided into intra-operative complications in 1.40% and postoperative complications in 9.18%. The annual incidences of intra- and postoperative complications were not significantly different from year to year (p = 0.314 and p = 0.112). Ureteral perforation, ureteral avulsion, and the intra-operative conversion rate were 1.35%, 0.03%, and 0.02%, respectively. Fever >38°C, septic shock, blood transfusion, and postoperative mortality were 7.44%, 0.81%, 0.07%, and 0.04%, respectively. Ureteral stricture occurred in 0.8% of cases. The median length of stricture site was 10.0 mm and the success rate of stricture treatment was 54.6%. CONCLUSION: Although URS-L utilization has increased in Japan, the annual complication rate has remained steady. Although URS-L is a useful and less invasive procedure, devastating complications can still occur.

[Etiological analysis of hydronephrosis in adults: A single-center cross-sectional study].

OBJECTIVE: To investigate the etiological distribution of hydronephrosis caused by upper urinary tract obstruction in adult patients and to improve the diagnostic accuracy for this condition. METHODS: The clinical information of adult patients with newly diagnosed hydronephrosis in Upper Urinary Tract Repair Outpatient Clinic of Peking University First Hospital from May 2020 to May 2021 were prospectively and continuously collected. Patients with ureteral calculi or upper urinary tract tumor were excluded. A total of 767 patients were involved. The underlying causes of upper urinary tract obstruction were identified by senior urological surgeons according to symptoms, medical history, physical examination, and a range of diagnostic imaging techniques including ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), retrograde pyelography, antegrade pyelography, radionuclide renogram and ureteroscopy. RESULTS: Among the 767 patients, 359(46.8%) were male and 408(53.2%) were female. The median age of these patients was 37 years (range, 14-84 years). Hydronephrosis was observed at left-sided in 357 cases(46.6%), right-sided in 251 cases(32.7%), and bilateral in 159 cases(20.7%). The causes of hydronephrosis were classified as follows: (1) Non-iatrogenic factors were found in 464 cases (60.5%). These included urinary malformations in 355 cases(76.5%), infection in 29 cases(6.3%), pelvic lipomatosis and/or cystitis glandularis in 23 cases(5.0%), ureteral endometriosis in 18 cases(3.9%), retroperitoneal fibrosis in 15 cases(3.2%), trauma in 7 cases(1.5%) and other non-iatrogenic factors in 12 cases(2.6%). Some of these patients had multiple non-iatrogenic causes. Among the 355 cases with urinary system malformations, 252 cases (71.0%) had ureteropelvic junction obstruction. (2) Iatrogenic ureteral injuries accounted for 210 cases (27.4%), including 112 cases(53.3%) of urological surgical injuries, 51 cases(24.3%) of radiotherapy for malignant tumor related injuries, 34 cases(16.2%) of gynecological and obstetrical surgical injuries, and 13 cases(6.2%) of general surgical injuries. (3) The cause of hydronephrosis remained unknown in 93 cases(12.1%). CONCLUSION: Hydronephrosis in adults due to upper urinary tract obstruction has a diverse range of causes, with urinary malformations and iatrogenic ureteral injuries being significant contributors. Urological surgeon involved in upper urinary tract reconstruction should be familiar with these potential causes to facilitate accurate diagnosis and effective treatment.

[Efficacy of coated metal ureteral stent in the treatment of pelvic lipomatosis induced hydronephrosis].

To investigate the initial experience of coated metal ureteral stent (CMUS) for treatment of pelvic lipomatosis induced hydronephrosis (PLH). The clinical and follow-up data of 8 patients who were diagnosed as PLH treated with CMUS in Peking University People's Hospital from August 2018 to February 2021 were retrospectively analyzed. Inclusion criteria included: Imaging evidence of excessive adipose tissue around the bladder in the pelvic cavity, bladder elevation in an "inverted pear shape", and bladder wall thickening; Cystoscopy indicated follicular hyperplasia of bladder mucosa and biopsy pathology indicated glandular cystitis; Unilateral or bilateral hydronephrosis and ureteromegaly. Exclusion criteria included: Ureteral atresia; Recurrent obstruction of the bladder outlet. Preoperative baseline data included age, gender, serum creatinine, pelvis width and ureteric stent symptoms questionnaire (USSQ) score. Intraoperative data included the location and length of ureteral stenosis observed by retrograde urography. Postoperative follow-up data included serum creatinine, pelvis width, and USSQ score. In the study, 8 patients (11 sides) with PLH were all male, with an average age of (38.7±8.6) years. Unilateral hydronephrosis was found in 5 cases and bilateral hydronephrosis in 3 cases. Preoperative mean serum creatinine was (90.0±10.3) µmol/L, and the mean renal pelvis width was (3.0±1.5) cm. The lower ureteral stricture was found in all cases, and the mean stricture length was (1.9±0.9) cm. Before operation, 3 patients had ureteral Double-J stents, with USSQ scores of 97.0, 68.0 and 100.0, respectively. Five patients underwent retrograde CMUS stenting, and 3 patients retrograde and antegrade. At the last follow-up, the average serum creatinine was (82.0±11.1) µmol/L and the mean renal pelvis width was (1.9±0.5) cm, which were significantly lower than those before operation (t=3.12, P=0.02; t=3.23, P=0.02). In the 3 patients with Double-J stent before surgery, the USSQ scores were 87.0, 62.0 and 89.0, respectively, which were significantly improved after CMUS stenting. The average follow-up time was (10.0±6.3) months. During the follow-up, 1 patient developed CMUS related symptoms, and no stent-associated infection and stent encrustation were found. In one case, the stent migrated to the bladder 3 months after operation, and the hydronephrosis disappeared after 3 months follow-up. CMUS stenting for treatment of PLH has certain efficacy and safety, which can explore a new therapeutic method for the long-term treatment of PLH.

Complications Subsequent to Urinary Tract Stent Placement: An Overview Focusing on the Imaging of Cancer Patients.

Ureteral involvement by a tumor is common, and both partial and complete obstructions can result in symptoms that are distressing and debilitating, especially in cancer patients for whom the resection of the primary tumor is not considered an option. Maintaining ureteric patency in these patients is a challenge. In addition, in cases where a patient has undergone nephroureterectomy due to primary transitional cell cancer, it becomes necessary to decompress the urinary tract to preserve the contralateral kidney from irreversible damage. This is possibly due to ureteral stenting, both retrograde and anterograde, and percutaneous nephrostomy (PCN). Since imaging plays an important role in the routine monitoring of stents, their more and more increasing use requires radiologists to be familiar with these devices, their correct position, their potential complications, and their consequences. The aim of this review is to offer a comprehensive review of the imaging features of some urinary stents and to show the complications encountered in cancer patients as a direct consequence of an invasive diagnostic or therapeutic procedure. Specifically, we focus on ureteral stents and PCN.